6 versus 8 volt batterry

HenryO

Member
Just purchased a 1944 Farmall A. It will start immediately when pulled but not with a 6 volt battery. Used a 12 volt straight to the starter and it started right up Wont start with the crank either so I figure we need some extre RPMS from more juice from the battery. I know that a 6 volt charger will suppply about 7 or slightly more volts. Have been told they work well iin a 6 volt system.. What say all you guys.?????? Thanks, Henry
 

Ya need to repair the mag, carb or whatever it needs and it will start fine with the crank or 6 volts.
 
What kevinj means is that an 8 volt battery is just a temporary fix for what is really wrong. Fix that and it starts like factory.
 
most of the guys on here will tell you to get the 6 volt system up to snuff and use large gauge battery cables. the hard part of adding an 8 volt battery is getting the 6 volt charging system to charge at a high enough rate to keep the 8 volt battery charged. Bill
 
Repair the 6V system and live with it's weak performance and constant need of attention or convert to 12V for a permanent fix..

8V cranks a little faster,but never works well for the rest of your electrical system. It takes 9+ volts from your over worked 6V generator to charge an 8V battery, and your 6V lights and battery ignition points and coil are shorter lived with that much (9+) volts feeding into them.
 
Well like he said, tractor was factory designed to function perfect with 6 volts, your tractor needs either rebuilt or in dire need of a TUNE UP.ave your batt money and fix it right, no SUBSTITUTION<
 
8V batteries are a band aid, fix it so it starts on 6V, then decide to stay there or go to 12V for convenience.
 
You need to buy a battery so your choice is to buy an 8 volt that solves your problem or spend
Big $$$ fixing the 6 volt and it still won"t start the tractor as good as an 8 will especially in cold weather.No brainer to me buy the 8 volt and let the "Battery Police" go nuts.
 
A gasser does not need high rpm cranking.
Diesels do require high rpm cranking.
Gassers need enough electrical system capacity to spark the plug. While the starter is drawing peak demand at the top of the compression stroke.
The tractor is suffering from low voltage to the coil. From a low capacity 6V battery, too small cables, high resistance connections. Odds are the coil polarity is backwards too. Did somebody slip a 12v coil into a 6V machine?
 
If it isn't a restoration I would convert to a 12v system just because it's simpler and more reliable.

Test your genny's output. If it's really good you can get by with an 8v just fine.

6v systems have to be perfect to work well. That was rare 50 years ago and that's why everyone stopped making equipment that used them. JMO
 
Or get a "big" six volt battery if you have room for it. We did that years ago with the Cockshutt 50 and 40 and it helped cranking speed a lot especially when very cold or very hot. I have a group 7D six volt battery on the 40 and it starts any time.
 
Had to laugh. Everyone is right about getting it tuned properly, but switching to an 8 volt battery works just fine. I put one in my 1936 HP 70 almost 6 years ago, still spins it over faster by quite a bit than the 6 volt battery.
Has not interfered with the ignition system or the lights.
I don't know if the generator only charges it to 7 or 7-1/2 volts but it spins faster and cranks longer if you have a problem than the 6 volt did.
 
As other said, 8 volt is a band aid. Unless the regulator is adjusted, it will not charge properly. Try and fix whatever is wrong so it starts and charges properly on 6 volts. Make sure all the high current cables are proper and have not been changed out for smaller gauge 12 volt cables. The starter might have issues, needs a rebuild?, that are hidden when cranked from 12 volts, but even after a conversion, they will reappear. If it seems to spin fast enough, check the coil. It might be the wrong one (12v with internal ballast) or simply weak.

I don"t understand the desire to convert all these old machines to 12 volts. As with anything, when properly maintained, it will work as good as new without modifications. I drive a 6 volt car on a daily basis, year round, with no problems at all. Lights, radio, heater, gauges, they all work properly.

Just needs a little troubleshooting and minor repair would be my guess.

Josh
 
A couple of things to check first.

What size battery cables are on it? They need to be 00 size if you're staying with 6 or 8 volt system. Every connection must be clean and tight. Also check the starter solenoid or mechanical switch, which ever it has. If it's heating up, it has high resistance.

Have you opened up the starter and checked the bushings? If the bushings are worn, the armature will drag on the field windings causing the starter to draw too many amps, robing the coil of enough voltage to fire.

If it's a mag ignition, might take a look at it, be sure the impulse is working, coil is good, etc.

If you're set on going with 8 volts, be sure to adjust the regulator up to about 9 volts, otherwise you'll have an 8 volt battery undercharged to 6 volts.
 
switch to 12 volts and don't look back,can be done using 6 volt gen and 12 volt reg or best route is and alternator
 
(quoted from post at 18:40:00 07/27/14) As other said, 8 volt is a band aid. Unless the regulator is adjusted, it will not charge properly. Try and fix whatever is wrong so it starts and charges properly on 6 volts. Make sure all the high current cables are proper and have not been changed out for smaller gauge 12 volt cables. The starter might have issues, needs a rebuild?, that are hidden when cranked from 12 volts, but even after a conversion, they will reappear. If it seems to spin fast enough, check the coil. It might be the wrong one (12v with internal ballast) or simply weak.

I don"t understand the desire to convert all these old machines to 12 volts. As with anything, when properly maintained, it will work as good as new without modifications. I drive a 6 volt car on a daily basis, year round, with no problems at all. Lights, radio, heater, gauges, they all work properly.

Just needs a little troubleshooting and minor repair would be my guess.

Josh

Josh, out in 6 land that may be true but up here in 3 land the temps get extremely cold during the winter months, couple that up with many older tractors having pop up piston kits with oversize bores as replacements at freshen up time and the 6 volt systems meet their limitations. M&amp;W corp made gear reduction units for the starters of that era but they were just a stop gap

I have recently retired after fifty + years doing exactly that kind of work for the same dealership.

During that time I have 12Vted dozens so active farmers could have reliable tractors for starting and many used 12V operated implements behind them. A proper conversion and the tractor is running immediately.

Purists will of course not be happy with me but in my business a satisfied customer who comes back saying how pleased he is is all i need to hear.

PS , 20 has been fairly hot recently , maybe I'll bump into you.

73s,

Mel KC3EH
 
The farm show magazine had an article in it you might be interested in. A company is making a battery (optima) that they tie two six volt batteries together to double the cranking amps. Kinda pricy but it will fit in the same size space as your original 6 volt battery.
 
Im NOT a fan of the oddball 8 volt system. If I was going to up voltage Id go ahead to the standard 12 volt system and be done with it as 6 or 12 (all the components) is more standard then trying to charge at 8 volts. I'm NOT saying 8 wont crank faster then 6 Billy Bob !!!

Even at 8 and especially 6 Id recommend 00 Gauge Battery and Starter and Ground cables and a well tuned ignition system.

At 6 you also want the absolute biggest heaviest highest rated battery you can fit into its compartment.

John T
 
Get the starter refreshed and good 1ga cables and it will start anytime i have 10 As and Bs and they start just fine but i have went thru the starters to make sure they are in shape. Clean up the commutator and new brushes,bearings sometimes a new Bendix and they will start great providing carb and dist,mag is working correct. Pulling and going to 12v just is a way of jump starting rather than fixing the system.
 

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